1. Field of the Invention
This invention relates to a pushbutton tuner, and more particularly to an improvement of placement of tuning coils so as to permit reduction in thickness of the pushbutton tuner.
2. Description of the Prior Art
In case of a pushbutton tuner, tuning is performed by the following operations: a pushbutton is pushed in; a button slide which carries the pushbutton moves inward of the tuner in accordance with movement of the pushbutton; a core mounted on a core slide which moves simultaneously with the button slide advances in the center of an associated tuning coil; and the amount of advancement of the core in the coil determines frequency to be received.
Such pushbutton tuner has a plurality of tuning coils. These coils have generally been disposed in alignment with the main surfaces thereof being in substantially same plane in the prior art. However, when the coils are disposed in this manner, the total width of the coils becomes so wide as to disturb placement of other members or to increase the size of the tuner normally enclosed in a housing.
In this connection, it has been proposed, also, to dispose the coils in two steps. FIG. 1 shows a part of such a conventional tuner in which the coils 1a and 1b are secured to a terminal board 2 as they are in two-decker state. The cores 3a and 3b advance in the coils 1a and 1b in response to advancement of a core slide 4 which moves simultaneously with a pivotal crank (not shown). The terminal board 2 is connected to a printed circuit board 6 by lead wires 7a and 7b.
In the pushbutton tuner of FIG. 1 with coils in two-decker arrangement, however, the height h at the portion of the tuning coils increases to thereby disturb reduction in size and thickness of the tuner. Further, since one of the lead wires 7a and 7b is inevitably longer, electric characteristic becomes bad particularly upon FM broadcasting reception.